This invention relates to the detection of nuclear radiation.
When a thermoluminescent phosphor is exposed to nuclear radiation while at a sufficiently low temperature, many of the free electrons or holes become trapped at lattice imperfections. They remain trapped for long periods of time when stored at that or a lower temperature. As the temperature is raised, the probability of escape is increased and the electrons (or holes) are released from the traps, subsequently returning to stable energy states, often with the emission of light. Materials which exhibit this characteristic are known as thermoluminescent dosimetry (TLD) materials, and an example of such a material is lithium fluoride.
Certain types of diamond, for example Type I industrial diamonds, are known to exhibit a certain degree of thermoluminescence.
U.S. Pat. No. 4,754,140 describes and claims diamond, particularly synthetic diamond, which has a nitrogen content not exceeding 100 ppm as a thermoluminescent material capable of detecting nuclear radiation. The diamond also preferably contains boron in an amount of 0.1 to 10 ppm.